Backing up a vehicle with a trailer attached is a difficult task for many drivers. This is particularly true for drivers that are untrained at backing up with a trailer attached, or drive with an attached trailer on an infrequent basis. To assist the driver in steering a vehicle with a trailer a Trailer Backup Assist (TBA) system is provided to assist the driver in maneuvering a vehicle with a trailer attached along a prescribed path. The driver may specify the trailer path curvature as the maneuver is executed.
Such TBA systems have TBA controller that uses trailer heading angle as an input in the control algorithm. Since a single vehicle may be attached to several trailers, it is desirable to use sensors on the towing vehicle to provide the trailer heading angle in order to avoid the cost and complexity associated with including the sensing capacity to each and ever trailer. Current TBA systems utilize a GPS system that compares to position estimates, an electronic compass, or inertial sensors, such as yaw rate sensors. However, each of these systems is expensive and complex.
There is a need to estimate trailer heading angle using sensors that are readily available on a towing vehicle.